This invention relates to cleaning of filters and in particular to a method and apparatus for cleaning air filters.
Air filters for domestic or industrial or vehicle air-conditioning equipment or for vehicle engines are generally of concertina or fan-folded paper or card formed into a cylindrical, conical or cube-like hollow core form open at each end. Some air filters are of foamed plastics material instead of paper or card. Whatever their composition, when such air filters become clogged they are removed and replaced by clean ones, Usually, and especially for vehicles, the clean filters used are brand new, and-the used air filters that are clogged by embedded particles in its wall are discarded and disposed of as a waste product.
Filter cleaning apparatus has been proposed, e.g. in U.S. Pat. No. 5584900, U.S. Pat. No. 3499267, U.S. Pat. No. 2406931, U.S. Pat. No. 2765048, U.S. Pat. No. 4154588, U.S. Pat. No. 4289510, U.S. Pat. No. 4704144, U.S. Pat. No. 5114444, U.S. Pat. No. 5143529, U.S. Pat. No. 5584900, U.S. Pat. No. 4842624, U.S. Pat. No. 3998656 and GSA-2174618 whereby air filters can be cleaned either in or after removal from the filtering equipment in which they are used. It is considered that such prior art filter cleaning apparatus have one or more disadvantages: For example they may be restricted to the cleaning of only one filter at a time and/or to the cleaning of filters of only.
One specific size and/or to the use of cumbersome mechanisms including movable suction heads and/or impacting heads to engage the surface of the filter to be cleaned. They are often time consuming to set up and/or are slow in effecting the intended cleaning operation A. particular problem which has not been satsfactorily addressed by the prior art filter cleaners is the elimination of vibration at caused by whirling as the filter spins. Experience shows that this effect is both alarming for the operator due to the noise and shaking of the machine, and causes damage to the filter and severe wear on the apparatus. Apparatus such as that disclosed in GB-A-2174618 rely mainly upon the delivery of high pressure air to the core of the spinning filter in order to clean the filter. This requires the provision of a high pressure air source and associated conduits to deliver the compressed air to the core of the filter. The core must be well sealed to prevent leakage and communication of the compressed air with the core is complicated by the requirement for seals around the deliver conduits.
It is an object of the present invention to provide a compact, economic, dry, filter cleaning apparatus which alleviates the disadvantages mentioned with reference to the prior art and so allows air filters to be reliably cleaned and recycled in order to reduce wastage and costs.
Accordingly the present invention provides apparatus for cleaning a hollow form filter comprising a housing defining a filter chamber, a rotatable deck to support one axial end of the filter, bearing means mounted on a swing arm which can be lifted and swung away from the axis of rotation of the filter to allow convenient insertion and removal of the filter in the filter chamber said bearing means rotatably mounting a spindle of conic shape for vertical movement to be received into the hollow axis of the filter to ensure alignment of the axis of rotation of the spindle, the deck and the filter, a motor coupled to rotate the deck and capable of a speed sufficient to discharge fouling into the filter chamber, and means to exhaust the fouling from the chamber.
Further according to the second aspect of the present invention there is provided a method of cleaning a hollow form filter comprising the steps of: spinning a fouled hollow form filter on its axis at a speed in the range of 750-1500 rpm sufficient to discharge the fouling from the filter, delivering a high pressure air flow to the hollow core of the filter and effectively sealing the top and base of the filter to expedite the discharge of fouling, isolating the filter and discharged fouling in a filter chamber of a housing and exhausting the discharged fouling from the filter chamber for collection and disposal, inducing a vacuum which sucks air and discharged fouling from the filter chamber to settle in a vacuum chamber.